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March, 1910 est practicable handiness. The bound- ing lines of the hull are all convex ' fore and aft to make it possible to spring off the dock under any condi- tions: ~The' stem fakes ait' as the result of the tumble-home sides and the stern is modeled of the compro- mise torpedo boat type, with a parabolic deck line of short radius to give in- creased water line length, simple con- struction and maximum available space in after compartments, with adequate protection for the twin propellers. The keel is built of 30-in. 20-Ib. flat plates for half the length amidships, "TAE MarRINE REVIEW Deck PLAN FrrReBoAtT DUWAMISH. Reverse frames, 2% x 2%x 5 Ib. angles, are carried alternately to deck stringer and to side stringer. Web frame plates are 12 in. wide, 14 Ib.; continuous through the side stringers. For half length amidship the floors are built of 16-in., 15-lb. plate, con- tinuous from bilge to bilge, reduced to 12%4-lb. forward and aft. The center keelson, side keelsons and bilge stringers are _ intercostal plates tied to the neighboring frame members with angles. The main deck beams, 6x 34% x 13.5 lb. angles, are spaced 22-in. cen- > a er ees ok eis E SECTION THROUGH BorreER Room Frresoat DUWAMISH. . reduced to 15-lb. at ends. The plates are single butt strapped and double riveted. The stem is forged 6x 1Y% in. and the rudder post 6 x 3 in. in section, The main frames are 34%x3x/79 Ib. angles spaced 22 inches and con- tinuous from center keelson to deck stringer. Thirty doubling bars the same size as the main frame angles are riveted over the keel. At the bulk- heads, partial bulkheads and webs the main frames are doubled, using 3 x 3 x 7.2 lb. angles. Stern cant frames are 3.x: 3.x 72 Ib. 'angeles. ters amidships and 44-in. centers at ends; there are two strong beams on frames 26 and 41 each built of two, 6 x 3% x 3% x 15-lb. channels placed back to back. The shell plating is as follows: : Pounds. Garboards, alltore and' att, <2 4062 15.0 Bilge strakes, for half length amidship.: 15.0 Bilge: -strakes,; at' €nds.. 42.522... 2... - 125 Bottom and side strakes, half length amidship... 14.0 2cuicscs beet <0 os ees 4.0 Bottom and side strakes, at ends...... 12.5 Topside strake, all fore and aft........ 12.5 Sheer strake, half length amidship 36 eo Wide s 5 5555 sees ws eke cries ie 18.0 Sheer strake, at. ends. 2.4.5... ees ais 15.0 The stern tubes are cast iron with 91 brass. sleeves carrying lignum vitae bearings at each end of the tube. The hull is divided into five water tight compartments by four water tight bulkheads. The bulkheads are all solid without doors or hatches except that between the engine and boiler rooms, which is fitted with water tight door. The main. deck is 334 x 3 mm fr, fastened by ™% in. galvanized deck screws. : ' The four boilers are situated for- ward, arranged in two banks facing athwartship; immediately aft of the boilers are situated the three vertical, reciprocating fire pumps, set athwart- ship. Aft of the fire pumps are two propelling engines, and at the extreme rear end of the engine room is the surface condenser arranged with - its axis athwartship. The various minof auxiliaries are placed on either side of the main engines. The boilers are of the Mosher water tube type, each having 2,250 sq. ft. of heating surface. built by the Mosher 'Water Tube Boiler Co., New York, and worked with nat-. ural draft. The working © steam pressure is 175 lbs. per sq. in. Crude oil is used for fuel, the oil 'being sup- plied to the furnaces through 16 Las- soe-Lovekin steam-atomized burners. The fuel oil is carried in one tank of 11,634 gallons capacity located in the forehold forward of the fire room bulkhead. Reciprocating fire pumps were adopt- ed instead of centrifugal pumps, such as have been installed in all of the recently built fire boats, for a number of reason'. It is said that the corros- ive action of the salt water of Elliot Bay, which is contaminated with sewage acids near the shore, is very severe and that centrifugal pumps fitted with brass runners and cast iron cases would require extensive repairs from time to time. The conclusions regarding the corrosion of the pumps are based on the experience of Seattle contractors who have used turbine pumps with salt water extensively. It is further claimed that the reciprocat-